Process for preparing 5-substituted pyrrolo-[2,3-D] pyrimidines

ABSTRACT

Processes for preparing 5-substituted pyrrolo[2,3-d]pyrimidines which are useful as intermediates for the preparation of pyrrolo[2,3-d]pyrimidine antineoplastic agents or as antineoplastic agents themselves are provided.

CROSS REFERENCE

This application is a division of application Ser. No. 08/066,831, filedon May 24, 1993, now U.S. Pat. No. 5,416,211, which is acontinuation-in-part of application Ser. No. 07/951,515, filed on Sep.25, 1992, now abandoned.

FIELD OF THE INVENTION

The invention relates to the field of pharmaceutical and organicchemistry and provides a process for preparing 5-substitutedpyrrolo[2,3-d]pyrimidine derivatives useful as intermediates in thepreparation of therapeutically active pyrrolo[2,3-d]pyrimidine-basedantifolates.

BACKGROUND OF THE INVENTION

Compounds known to have antifolate activity are well recognized aschemotherapeutic agents for the treatment of cancer. One such agent,methotrexate, is now one of the most widely used anticancer drugs; andmany other compounds in the folic acid family have been synthesized,tested and discussed in the chemical and medical literature. Thecompounds have various activities at the enzymatic level. In particular,they inhibit such enzymes as dihydrofolate reductase, folatepolyglutamate synthetase, glycinamide ribonucleotide formyltransferaseand thymidylate synthase.

More recently, a series of 4-hydroxypyrrolo[2,3-d]pyrimidine-L-glutamicacid derivatives have been disclosed and shown to be particularly usefulantifolate drugs. See, e.g., Akimoto, et al., European PatentPublication 0 434 426.

5-Substituted pyrrolo[2,3-d]pyrimidine compounds of the formula I##STR1## wherein R is NHC*H(COOR¹)CH₂ CH₂ COOR¹ or OR¹ ;

each R¹ is H or the same or different carboxy protecting group;

the configuration about the carbon atom designated * is L;

n is 0 or 1; and

A is an aryl group which may be substituted, are useful in preparingvarious 5-substituted pyrrolo[2,3-d]pyrimidine-based therapeutic agentsor, when R is NHC*H(COOR¹)CH₂ CH₂ COOR¹ and each R¹ is H, or a saltthereof, are useful as therapeutic agents.

The art recognizes multiple methods for the preparation ofpyrrolopyrimidine derivatives. See, e.g., U.S. Pat. No. 4,997,838; Miwa,et al., J. Med. Chem., 34: 555-560 (1991); C. W. Noell, et al., J.Heterocyclic Chem., 1: 34-41 (1964); Kandasamy Ramasamy, et al., J.Chem. Soc., Chem. Commun., 560-562 (1989); and John A. Secrist, et al.,J. Org. Chem., 43: 3937-3941 (1978).

The present invention provides regiospecific processes for preparing5-substituted pyrrolo[2,3-d]primidines which are useful as intermediatesfor the preparation of, inter alia, pharmaceutically activepyrrolo[2,3-d]pyrimidine compounds, or as pharmaceutically activecompounds.

The present invention further provides a regiospecific process forpreparing 5-substituted pyrrolo[2,3-d]pyrimidine compounds, wherein saidprocess is carried out in the same vessel.

SUMMARY OF THE INVENTION

This invention provides a process for preparing 5-substitutedpyrrolo[2,3-d]pyrimidines of formula I ##STR2## wherein R isNHC*H(COOR¹)CH₂ CH₂ COOR¹ or OR¹ ;

each R¹ is H or the same or different carboxy protecting group;

the configuration about the carbon atom designated * is L;

n is 0 or 1; and

A is an aryl group which may be substituted;

or a salt thereof, which comprises

a) reacting 2,4-diamino-6-hydroxypyrimidine with a haloaldehyde offormula II ##STR3## wherein Y is bromo, chloro or iodo; and

A, R, R¹, A and * are as defined above; and

b) optionally salifying the reaction product from step a).

The present invention also provides a process for preparing5-substituted pyrrolo[2,3-d]pyrimidines of formula I ##STR4## wherein R,R¹, A, n and * are as defined above, or a salt thereof, which comprises

a) reacting a halogenating agent with a compound of formula III ##STR5##wherein

R, R¹, A, n and * are as defined above; and

R² is a substituent of formula IV, V, or VI ##STR6## wherein R³ is OR⁴,wherein R⁴ is a hydroxy protecting group;

OCOR⁵, wherein R⁵ is C₁ -C₆ alkyl, phenyl, benzyl or C₃ -C₆ cycloalkyl;

NR⁶ R⁷, wherein R⁶ and R⁷ are independently C₁ -C₆ alkyl, C₃ -C₆cycloalkyl, or are taken together with the nitrogen atom and,optionally, an oxygen atom, to form a 5- to 6-membered saturatedmonocyclic group which optionally may be substituted with one or twosubstituents selected from the group consisting of C₁ -C₄ alkyl and C₁-C₄ alkoxy; or

R⁸ and R⁹ each are C₁ -C₄ alkyl or are taken together with the oxygenatoms to form a 5- to 6-membered saturated monocyclic group whichoptionally may be substituted with one or two substituents selected fromthe group consisting of hydroxy, C₁ -C₄ alkyl, and C₁ -C₄ alkoxy;

b) reacting the reaction product from step a) with2,4-diamino-6-hydroxypyrimidine; and

c) optionally salifying the reaction product from step b).

DETAILED DESCRIPTION OF THE INVENTION

Throughout this document, all temperatures are in degrees Celsius andall expressions of proportion, percentage, and the like, are in weightunits, except for solvents or mixtures thereof which are in volumeunits.

The term "C₁ -C₄ alkyl" refers to straight or branched aliphatic chainsof 1-4 carbon atoms such as, for example, methyl, ethyl, propyl,isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl.

The term "C₁ -C₆ alkyl" refers to C₁ -C₄ alkyl plus the straight andbranched aliphatic chains of 5-6 carbon atoms including, for example,n-pentyl, isopentyl, neopentyl, n-hexyl, isohexyl, 3-methylpentyl,2,3-dimethylbutyl, and the like.

The term "aryl", as used in describing the ring structure identified asA in formulae I, II, III, and VII refers to 5- to 6-membered aromaticresidues, including heterocyclic groups containing up to threeheteroatoms (e.g., N, O and S) contained therein, such as, for example,phenyl, especially 1,4-phenylene, thienyl, pyridyl, furyl, and the like.Such aryl groups optionally may be substituted, in addition to the CORgroup, with one or two substituent groups selected from halo, hydroxy,C₁ -C₄ alkyl, and C₁ -C₄ alkoxy. Other than unsubstituted 1,4-phenylene,a single additional substitution of A at the 2-position relative to the1-position COR functionality is preferred.

The term "C₁ -C₄ alkoxy" refers to an alkyl group of 1 to 4 carbon atomsattached through an oxygen bridge such as for example, methoxy, ethoxy,n-propoxy, isopropoxy, and the like.

The term "halo" refers to bromo, chloro, fluoro and iodo.

The term "C₃ -C₆ cycloalkyl" refers to a saturated hydrocarbon ringgroup having from 3 to 6 carbon atoms including, for example,cyclopentyl and cyclohexyl.

As used herein, the carboxy protecting group of R¹, where R¹ is otherthan H, and the hydroxy protecting group of R⁴ denote groups whichgenerally are not found in the final therapeutic compounds but areintentionally introduced during a portion of the synthetic process toprotect a group which otherwise might react in the course of chemicalmanipulations, and is later removed. Since compounds bearing one or moreprotecting groups are of importance primarily as chemical intermediates(although some protected derivatives also exhibit biological activity),their precise structure is not critical. Numerous reactions for theformation and removal of such protecting groups are described in anumber of standard works including, for example, Protective Groups inOrganic Chemistry, Chapter 3 (McOmie Ed., Plenum Press, 1973); Green,Protective Groups in Organic Synthesis, Chapter 2 (John Wiley, 1981);and Schrooder and Lubke, The Peptides, Vol. I (Academic Press, 1965).

Carboxy groups can be protected as an ester group which is selectivelyremovable under sufficiently mild conditions so as not to disrupt thedesired structure of the molecule. Esters suitable for use in protectingthe carboxy group include branched C₁ -C₆ alkyl esters such as t-butyl,and esters substituted with (i) C₁ -C₄ alkoxy such as methoxymethyl,1-methoxyethyl, ethoxyethyl, and the like; (ii) C₁ -C₆ alkylthio such asmethylthiomethyl, 1-ethylthioethyl and the like; (iii) halo such as2,2,2-trichloroethyl, 2-bromoethyl, 2-iodoethoxycarbonyl, and the like;(iv) 1 to 3 phenyl groups each of which may be unsubstituted or mono-,di-, or tri-substituted with C₁ -C₆ alkyl, C₁ -C₄ alkoxy, hydroxy, haloand nitro such as 4-nitrobenzyl; or (v) aroyl such as phenacyl. Whenmore than one carboxy group is present, each carboxy protecting groupmay be the same or may be different. It is preferred that each is thesame group. Preferred protecting groups are C₁ -C₆ alkyl esters such asmethyl ester or ethyl ester.

Preferred hydroxy protecting groups include ether groups such as C₁ -C₄alkyl ether, phenyl ether, and silyl ether. Particularly useful silylether groups include, for example, tri-isopropylsilyl ether,trimethylsilyl ether, triethylsilyl ether, and t-butyldimethylsilylether (see, e.g., Colvin, E. W., Silicon Reagents in Organic Synthesis,(Academic Press, 1988).

The compounds of formula I exist in tautomeric equilibrium with thecorresponding 4(3H)-oxo compounds. For illustrative purposes, theequilibrium for the pyrrolopyrimidine ring system, and the numberingthereof, are shown below: ##STR7##

For convenience, the 4(3H)-oxo form is depicted in formula I, and thecorresponding nomenclature is used throughout this specification.However, it is understood that such depictions include the correspondingtautomeric 4-hydroxy form.

The present process requires reacting 2,4-diamino-6-hydroxypyrimidinewith a haloaldehyde of formula II in a solvent, under conditions whichfavor cyclization.

The 2,4-diamino-6-hydroxypyrimidine starting material employed in thepresent process is commercially available, whereas preparation of thehaloaldehydes of formula II, when R is OR¹ and R¹ is H or a carboxyprotecting group, is known in the art (see, e.g., DeGraw, et al., J.Med. Chem., 25: 1227-1230 (1982).

DeGraw teaches the preparation of a formula II compound where A is1,4-phenylene, n is 0, R is OR¹, and R¹ is H. Methods for protection ofthe carboxylic acid group and preparation of a formula II compound wheren is 1 are well known.

An alternative starting material for formula II is prepared bycondensing an enol ether of formula VII ##STR8## wherein A is an arylgroup which may be substituted;

R is OR¹ ;

R¹ is H or a carboxy protecting group;

n is 0 or 1;

R³ is OR⁴ ; and

R⁴ is a hydroxy protecting group, as generally described by DeGraw,supra, with a compound of formula VIII ##STR9## wherein each R^(1') isthe same or different carboxy protecting group and the configurationabout the carbon atom designated * is L, using conventional condensationtechniques. One preferred condensation method, when R of a formula IIcompound is H, is taught by Taylor, et al., in U.S. Pat. No. 4,684,653.Otherwise, a formula II compound should first be deprotected prior tocondensation.

Upon completion of condensation, the reaction product is halogenated viaknown procedures (see, e.g. DeKimpe, supra) using an appropriatehalogenating agent, to give a formula II starting material where R isNHC*H(COOR¹)CH₂ CH₂ COOR¹, Y is bromo, chloro or iodo, and R¹, n and *are as defined above.

Particularly appropriate halogenating agents include, for example,elemental bromine, chlorine, and iodine, N-bromo-, N-chloro-, andN-iodosuccinimide, N-bromo-, N-chloro-, and N-iodophthalimide, and thelike.

Thus, this first aspect of the present invention provides a process forpreparing 5-substituted pyrrolo[2,3-d]pyrimidines of formula I ##STR10##wherein R is NHC*H(COOR¹)CH₂ CH₂ COOR¹ or OR¹ ;

each R¹ is H or the same or different carboxy protecting group;

the configuration about the carbon atom designated * is L;

n is 0 or 1; and

A is an aryl group which may be substituted;

or a salt thereof, which comprises

a) reacting 2,4-diamino-6-hydroxypyrimidine with a haloaldehyde offormula II ##STR11## wherein Y is bromo, chloro or iodo; and

A, R, R¹, n and * are as defined above; and

b) optionally salifying the reaction product from step a).

The above-described reaction is run in the presence of an appropriatesolvent which includes, for example, C₁ -C₄ alcohol, acetonitrile,dimethylformamide (DMF), dimethylsulfoxide (DMSO), dimethylacetamide,N-methylpyrrolidinone, water, and mixtures thereof. Preferred is amixture of solvents which includes ethanol and water, or acetonitrileand water.

The amount of time needed for this reaction to run to completion will berecognized by one of ordinary skill in the art. Chromatographictechniques such as TLC and HPLC will assist in determining thecompletion of this reaction.

The temperature employed in this step should be sufficient to effectcompletion of this reaction. Typically, temperature ranges from about25° C. to about 100° C. are preferred, while a range from about 70° C.to about 90° C. is especially preferred.

Otherwise, formula I compounds prepared by this process are readilyisolated by ordinary procedures and require no furher purification foruse as intermediates.

Another aspect of the present invention is a process for preparing5-substituted pyrrolo[2,3-d]pyrimidines of formula I which comprises

a) reacting a halogenating agent with a compound of formula III##STR12## wherein R, R¹, A, n and * are as defined above; and

R² is a substituent of formula IV, V, or VI ##STR13## wherein R³ is OR⁴,wherein R⁴ is a hydroxy protecting group;

OCOR⁵, wherein R⁵ is C₁ -C₆ alkyl, phenyl, benzyl or C₃ -C₆ cycloalkyl;

NR⁶ R⁷, wherein R⁶ and R⁷ are independently C₁ -C₆ alkyl, C₃ -C₆cycloalkyl, or are taken together with the nitrogen atom and,optionally, an oxygen atom, to form a 5- to 6-membered saturatedmonocyclic group which optionally may be substituted with one or twosubstituents selected from the group consisting of C₁ -C₄ alkyl and C₁-C₄ alkoxy; or

R⁸ and R⁹ each are C₁ -C₄ alkyl or are taken together with the oxygenatoms to form a 5- to 6-membered saturated monocyclic group whichoptionally may be substituted with one or two substituents selected fromthe group consisting of hydroxy, C₁ -C₄ alkyl, and C₁ -C₄ alkoxy;

b) reacting the reaction product from step a) with2,4-diamino-6-hydroxypyrimidine; and

c) optionally salifying the reaction product from step b).

The preparation of an aldehyde of formula III (where R² is a substituentof formula IV) is known in the art (see, e.g. Taylor, et al., J. Med.Chem., 55: 3222-3227 (1990).

Taylor teaches the preparation of a formula III compound where R is OR¹,R¹ is methyl, n is 0 or 1, and R² is a substituent of formula IV. Thealdehyde of formula III may further be modified to form enamines, enolesters, enol ethers, (where R² is a substituent of formula V), andacetals (where R² is a substituent of formula VI), by processes known inthe organic chemical art. Thus, the starting material of this aspect ofthe present invention includes the aldehyde, enol ether, enol ester,enamine and acetal forms of formula III compounds.

An enol ether of formula III where R is OR¹, R¹ is a carboxy protectinggroup, R² is a substituent of formula V, R³ is OR⁴, and R⁴ is a hydroxyprotecting group (especially methyl) is the preferred formula IIIstarting material.

Alternatively, an enol ether starting material of formula III may beprepared by condensing the above-described, preferred enol ether offormula III with a compound of formula VIII as described above. FormulaIII compounds, where R is OR¹ and R¹ is a carboxy protecting grouppreferrably are deprotected prior to condensation. However, it ispreferred to carry out this condensation following completion of theinstant process.

Once a formula III starting material is selected and added to anappropriate solvent, it is first reacted with a halogenating agent, andthe reaction product from the first step is reacted with2,4-diamino-6-hydroxypyrimidine. The reaction product from this stepoptionally may be salified using conventional procedures.

Appropriate and preferred solvents, temperature, reaction time andisolation procedures for this process are as described above for thecyclization of compounds of formula II compounds to compounds of formulaI.

In the preparation of formula I compounds using the present process,each step may be carried out independently wherein the reaction productfrom each step is isolated and purified or, preferably, carried out insitu as a process wherein each step of the process is sequentiallycarried out in the same vessel.

Formula I compounds, when R is OR¹, and R¹ is H or a carboxy protectinggroup, or when R is NHC*H(COOR¹)CH₂ CH₂ (COOR¹), and R¹ is the same ordifferent carboxy protecting group, are intermediates useful for thepreparation of, inter alia, therapeutically activepyrrolo[2,3-d]pyrimidine antifolate agents.

When R is OR¹ and R¹ is H, or, following the preferred deprotection stepwhen R¹ is a carboxy protecting group, a formula I compound first mustbe condensed with a compound of formula VIII above. Followingcondensation, if R¹ is H, the product is in a final form which is readyfor pharmaceutical use. If R¹ is a carboxy protecting group, such aprotecting group may be removed and the resulting product is atherapeutically active antifolate.

Likewise, a formula I compound, when R is NHC*H(COOR¹)CH₂ CH₂ (COOR¹)and R¹ is H, is therapeutically active as a reaction product of theprocesses of the present invention. Otherwise, when R¹ is a carboxyprotecting group, it, too, must be removed by standard methods toprovide a therapeutically active agent.

Once therapeutically active pyrrolo[2,3-d]pyrimidine antifolates areprepared, conversion to a salt form will provide morepharmaceutically-acceptable compounds.

The following examples illustrate specific aspects of the presentinvention and are not intended to limit the scope thereof in any respectand should not be so construed.

PREPARATION 1 Methyl 4-(4-trimethylsilyloxy-3-butenyl)benzoate

To 3.65 g (17.7 mmol) of 4-(4-carbomethoxyphenyl)butanal and 3.43 g(21.2 mmol) of 1,1,1,3,3,3-hexamethyldisilazane in 177 ml of methylenechloride in a nitrogen atmosphere was added 3.89 g (19.5 mmol)trimethylsilyl iodide at -15° C. over 2 minutes. The mixture was stirredfor 10 minutes then allowed to come to room temperature. After 2 hours,the excess reagent was quenched by addition of 100 ml water. The layerswere separated and the organic phase dried over sodium sulfate. Thesolvent was removed by vacuum concentration to give 5.0 g of methyl4-(4-trimethylsilyloxy-3-butenyl)benzoate in a yield of 100 percent.Thin Layer Chromatography (TLC) analysis (silica; hexane--ethyl acetate3:2) indicated that the above product was substantially pure, b.p. 170°C.@ 0.12 torr. ¹ H NMR (CDCl₃) δ 0.15 (s, 9H), 2.41 (q, J=7.2 Hz, 2H),2.69 (m, 2H), 3.89 (s, 3H), 4.47 (q, J=7.2 Hz, 1H), 6.15 (m, 1H), 7.25(d, J=8.2 Hz, 2H), 7.93 (d, J=8.2 Hz, 2H); ¹³ C NMR (CDCl₃) δ -0.60,25.0, 35.9, 51.8, 109.8, 128.4, 128.5, 129.6, 138.6, 148.0, 167.1; FDMS279 (90), 278 (M⁺, 100%) 280, 251, 226; An analytical sample wasobtained by flash chromatography (silica; hexane--ethyl acetate 3:2).Anal. for C₁₅ H₂₂ O₃ Si, Calcd: C, 64.71; H, 7.96; Found: C, 64.90; H,8.05.

PREPARATION 2 2-Bromo-4-(4-carbomethoxyphenyl)butanal

To 4.46 g (16 mmol) of methyl 4-(4-trimethylsilyloxy-3-butenyl)benzoate,prepared in Preparation 1, in 16 ml carbon tetrachloride at -20° C. wasslowly added 2.56 g (16 mmol) of bromine in 16 ml carbon tetrachlorideover 4 hours. The mixture was allowed to come to room temperature thendecanted from a small amount of insoluble material. The solvent wasremoved by vacuum rotary evaporation to give 4.60 g of2-bromo-4-(4-carbomethoxyphenyl)butanal. Chromatography purification(silica; hexane--ethyl acetate 7:3) of the above product gave 4.0 g in ayield of 87.8 percent. ¹ H NMR (CDCl₃) δ 2.24 (m, 1H), 2.36 (m, 1H),2.81 (m, 1H), 2.90 (m, 1H), 3.90 (s, 3H), 4.16 (m, 1H), 7.27 (d, J=8.2Hz, 2H), 7.97 (d, J=8.2 Hz, 2H), 9.46 (d, J=2.1 Hz, 1H); ¹³ C NMR(CDCl₃) δ 32.5, 32.7, 51.7, 54.3, 128.3, 128.4, 129.8, 145.0, 166.6,192.0.

EXAMPLE 34-(2-[2-Amino-4-oxo-3,7-dihydropyrrolo[2,3-d]pyrimidin-5-yl]ethyl)benzoicAcid Methyl Ester

To 1.69 g (13.4 mmol) of 2,4-diamino-6-hydroxypyrimidine, 2.20 g (26.8mmol) of sodium acetate and 20 ml of water at 80° C. were added 3.82 g(13.4 mmol) of 2-bromo-4-(4-carbomethoxyphenyl)butanal, prepared inPreparation 2, in 7 ml of methanol over 5 minutes. The mixture wasmaintained at 80° C. for 5 minutes, cooled to room temperature andstirred for 30 minutes. The mixture was filtered, washed with water, anddried for 18 hours at 50° C. @ 10 torr to provide 3.32 g of4-(2-[2-amino-4-oxo-3,7-dihydropyrrolo[2,3-d]pyrimidin-5-yl]ethyl)benzoicacid methyl ester (m.p.>220° C.) in a yield of 79.4 percent. Theremaining filtrate was cooled to 5° C. and filtered to provide anadditional 0.069 g of the above product, for a combined yield of 81percent. ¹ H NMR (DMSO-d6) δ 2.80 (m, 2H), 2.93 (m, 2H), 3.78 (s, 3H),5.97 (s, 2H), 6.26 (d, J=2.0 Hz, 1H), 7.28 (d, J=8.2 Hz, 2H), 7.80 (d,J=8.2 Hz, 2H), 10.12 (s, 1H), 10.58 (s, 1H); FDMS 312 (M⁺), Anal. forC₁₆ H₁₆ N₄ O₃, Calcd: C, 61.53; H, 5.16; N, 17.94; Found: C, 61.79; H,5.33; N, 17.66.

PREPARATION 44-[2-(2-Amino-4,7-dihydro-4-oxo-3H-pyrrolo[2,3-d]pyrimidin-5-yl)ethyl]benzoicAcid

A mixture of 3.17 g (10.15 mmol) of4-[2-(2-amino-4,7-dihydro-4-oxo-3H-pyrrolo[2,3-d]pyrimidin-5-yl)ethyl]benzoicacid methyl ester, prepared in Example 3, in 30 ml of 1N aqueous sodiumhydroxide and 5 ml methanol was stirred for 20 hours at roomtemperature. Tetrahydrofuran 5 ml) was added and the mixture was stirredfor 4 hours then neutralized with 30 ml of 1N aqueous hydrochloric acid.The resulting precipitate was separated by filtration, washed with water(20 ml) and dried in a vacuum oven at 50° C. to obtain 2.65 g of theabove product in a yield of 87 percent. ¹ H NMR (DMSO-d₆) δ 2.45 (m,2H), 2.91 (m, 2H), 5.99 (s, 2H), 6.27 (d, J=2.0 Hz, 1H), 7.27 (d, J=8.2Hz, 2H), 7.79 (d, J=8.2 Hz, 2H), 10.14 (s, 1H), 10.59 (d, J=2.0 Hz, 1H),13.2 (bs, 1H).

PREPARATION 5N-[4-[2-[2-Amino-4,7-dihydro-4-oxo-3H-pyrrolo[2,3-d]pyrimidin-5-yl]ethyl]benzoyl]glutamicAcid Dimethyl Ester

To 2.00 g (6.74 mmol) of4-[2-(2-amino-4,7-dihydro-4-oxo-3H-pyrrolo[2,3-d]pyrimidin-5-yl)ethyl]benzoicacid, prepared in Preparation 4, in 23 ml dimethylformamide undernitrogen was added 1.40 g (13.8 mmol) of N-methylmorpholine and 1.17 g(6.70 mmol) of 4-chloro-2,6-dimethoxytriazine. The formation of theactive ester was monitored by the HPLC analysis of aliquots. After 40minutes at room temperature 0.70 g (6.9 mmol) of N-methylmorpholine wasadded followed by 1.56 g (7.37 mmol) L-glutamic acid dimethyl esterhydrochloride. After 30 minutes HPLC analysis indicated substantiallycomplete consumption of the active ester and formation ofN-[4-[2-[2-Amino-4,7-dihydro-4-oxo-3H-pyrrolo[2,3-d]pyrimidin-5-yl]ethyl]benzoyl]glutamicacid dimethyl ester. The reaction mixture was filtered and the aboveproduct concentrated and purified by silica chromatography (elution 1:4methanol:methylene chloride). The pure fractions were pooled andprovided 1.30 g of the above product in a yield of 43 percent. ¹ H NMR(DMSO-d₆) δ 2.01 (m, 2H), 2.40 (t, J=7.4 Hz, 2H), 2.80 (m, 2H), 2.92 (m,2H), 3.53 (s, 3H), 3.59 (s, 3H), 4.40 (m, 1H), 5.99 (s, 2H),6.26 (d,J=1.9 Hz, 1H), 7.23 (d, J=8.2 Hz, 2H), 7.73 (d, J=8.2 Hz, 2H), 8.62 (d,J=7.5 Hz, 1H), 10.15 (s, 1H), 10.57 (d, J=1.9 Hz, 1H).

PREPARATION 6N-[4-[2-[2-Amino-4,7-dihydro-4-oxo-3H-pyrrolo[2,3-d]pyrimidin-5-yl]ethyl]benzoyl]glutamicAcid

A mixture of 0.50 g (1.1 mmol) ofN-[4-[2-[2-amino-4,7-dihydro-4-oxo-3H-pyrrolo[2,3-d]pyrimidin-5-yl]ethyl]benzoyl]glutamicacid dimethyl ester, prepared in Preparation 5, and 3.3 ml of 2N aqueoussodium hydroxide was stirred at room temperature for 48 hours andneutralized to a pH of 5 with 6M aqueous hydrochloric acid. Theprecipitate was filtered, washed with water and dried, to give 0.277 gof the above product in a yield of 59 percent.

PREPARATION 7 1-Methoxy-4-(4-carboxymethylphenyl)-1-butene

To 3.77 g (11 mmol) of methoxymethyltriphenyl phosphonium chloride in 10ml of toluene at 0° C. under nitrogen was added 11 ml (11 mmol) of 1Mpotassium t-butoxide in tetrahydrofuran over 20 minutes. The resultingsolution was stirred for 10 minutes, then 1.92 g (10 mmol) of3-(4-carboxymethylphenyl)-propanal in 10 ml of toluene was added over 15minutes. After stirring the mixture for 20 minutes 40 ml of ethyl etherwere added. The resulting precipitate was filtered with diatomaceousearth, collected, washed with 20 ml of water, 20 ml of saturated sodiumchloride and dried with a 9:1 sodium sulfate:saturated sodium chloridemixture. Vacuum concentration of the filtered solution and triturationof the residue with hexane gave 1.72 g of 1-methoxy-4-(4-carboxymethylphenyl)-1-butene. Chromatography of the above product (silica gel, 8:2hexane:ethyl acetate) gave 1.0 g of a mixture of geometric isomers(Z/E-6:4) of the above product in a combined yield of 45 percent. b.p.140° C. @ 0.07 torr. ¹ H NMR (CDCl₃) δ 2.23 (dq, J=1.0, 8.1 Hz), 2.40(dq, J=1.3, 8.0 Hz) total 2H, 2.70 (t, J=8.1 Hz), 2.71 (t, J=8.0 Hz),total 2H, 3.48 (s), 3.55 (s), total 3H, 3.89 (s), 3.90 (s), total 3H,4.32 (q, J=6.2 Hz), 4.71 (dr, J=7.3, 12.6 Hz), total 1H, 5.87 (dt,J=1.3, 6.2 Hz), 6.28 (dt, J=1.0, 12.6 Hz), total 1H, 7.23 (d, J=8.2 Hz),7.27 (d, J=8.2 Hz), total 1H, 7.94 (d, J=8.2 Hz), 7.95 (d, J=8.2 Hz),total 2H; ¹³ C NMR (CDCl₃) δ 25.2, 29.3, 36.0, 37.4, 51.9, 56.0, 59.5,101.8, 101.9, 105.5, 127.9, 128.0, 128.5, 128.6, 129.6, 129.7, 146.9,147.5, 147.9, 148.0, 167.1, 167.2; IR (CHCl₃) 3025, 2954, 1716, 1656,1610, 1437, 1284, 1112 cm⁻¹ ; MS(FD) m/z 220 (M⁺).

EXAMPLE 84-(2-[2-amino-4(1H)-oxo-4,7-dihydropyrrolo[2,3-d]pyrimidin-5-yl]ethyl)benzoicAcid Methyl Ester

To 1.10 g (5.0 mmol) of the1-methoxy-4-(4-carboxymethylphenyl)-1-butene, prepared in Preparation 7,in 10 ml of acetonitrile was added 10 ml of water. The resulting mixturewas cooled to 5° C. and 0.80 g (1.0 equiv) of bromine were added. A 0.63g (5.0 mmol) of 2,4-diamino-6-hydroxypyrimidine was added and themixture was stirred and warmed to 80° C. After 40 minutes the mixturewas cooled to room temperature and 20 ml of water were added. The pH ofthe resulting slurry was adjusted to 6 with 5N sodium hydroxide. Theprecipitate was collected by filtration, washed with water, and dried at50° C. @ 10 torr to obtain 1.44 g of the above product in a yield of 92percent.

EXAMPLE 94-(2-[2-amino-4(1H)-oxo-4,7-dihydropyrrolo[2,3-d]pyrimidin-5-yl]ethyl)benzoyl-L-glutamicAcid Diethyl Ester

To 300 mg (0.766 mmol) of N-4-(1-methoxy-1-buten-4-yl)benzoyl-L-glutamicacid diethyl ester, 3.0 ml of acetonitrile, and 3.0 ml of water, stirredat room temperature, are added 122 mg (0.766 mmol) of bromine in 1 ml ofacetonitrile. To this solution is added 188 mg (2.3 mmol) of sodiumacetate and 0.97 mg (0.77 mmol) of 2,4-diamino-6-hydroxypyrimidine andthe resulting mixture is heated to 60° C. for 18 hours, cooled, thenconcentrated under vacuum. The resulting residue is triturated (2×5 mlof water) and decanted. Ethanol (5 ml) and 440 mg (2.3 mmol) ofp-toluenesulfonic acid monohydrate are added. After heating under refluxfor 20 minutes the mixture is cooled to room temperature and filtered.The precipitate is washed with ethanol (2×5 ml) and dried to obtain ap-toluenesulfonate salt of the title compound.

The present invention has been described in detail, including thepreferred embodiments thereof. However, it will be appreciated thatthose skilled in the art, upon consideration of the present disclosure,may make modifications and/or improvements that fall within the scopeand spirit of the invention as set forth in the following claims.

What is claimed is:
 1. A process for preparing 5-substitutedpyrrolo[2,3-d]pyrimidines of formula I ##STR14## wherein R isNHC*H(COOR¹)CH₂ CH₂ COOR¹ or OR¹ ;each R¹ is H or the same or differentcarboxy protecting group; the configuration about the carbon atomdesignated * is L; n is 0 or 1; A is an aryl group which may besubstituted; or a salt thereof, which comprises a) reacting ahalogenating agent with a compound of formula III ##STR15## wherein R,R¹, A, n and * are as defined above; and R² is formula IV

    OHC--CH.sub.2 --CH.sub.2                                   (IV);

b) reacting the reaction product from step a) with2,4-diamino-6-hydroxypyrimidine at a temperature ranging from about 25°C. to about 100° C.; in a solvent selected from the group consisting ofC₁ -C₄ alcohol, acetonitrile, dimethylformamide, dimethylsulfoxide,dimethylacetamide, N-methylpyrrolidinone, water, and mixtures thereof;and c) optionally salifying the reaction product from step b).
 2. Theprocess of claim 1 wherein the halogenating agent is elemental bromineor chlorine.
 3. The process of claim 1 wherein steps a) and b) arecarried out in the same vessel.
 4. The process of claim 1 wherein stepsa), b), and c) are carried out in the same vessel.